Old Post Office Tower is at 1100 Pennsylvania Ave. N.W. (at 12th St.). Designed in the Romanesque Revival style and completed in 1899, the former Old Post Office Pavilion served as the nation's postal headquarters until 1914. The building was nearly demolished twice—in the 1920s and again in the 1970s as the Federal Triangle complex took shape—before a 1980s renovation that added a food court and retail space turned it into a popular tourist attraction.
The 315-foot clock tower houses 10 bells, a gift from Great Britain in honor of the nation's Bicentennial. A glass elevator ascends to the bell-ringing chamber; an observation deck at the 270-foot level offers a panoramic view of downtown Washington.
Note: The tower and observation deck remain closed pending the building's ongoing conversion to a luxury hotel. Guided tower tours may resume when the hotel opens in late 2016 or early 2017.